Super-Earth Found Hiding in Gliese 581 Star System After All

Gliese, or GJ, 581 - a star 20 light years from here

The Gliese 581 star system is roughly 20 light years away from Earth. If we could travel at the speed of light as a species, Gliese 581 is a place a human could visit in a single human lifetime. It is an M3 dwarf star, which is to say it is a Red Dwarf star. This means that its light is relatively faint compared to our Sun (which is a Yellow Dwarf star) and considerably smaller than our Sun, too. Scientists once felt that red dwarfs weren't places you would expect to find habitable worlds, but now - considering that red dwarfs make up maybe 70% of the Milky Way Galaxy - scientists are reconsidering. The Gliese 581 system is a good example of this change in attitude. Previous to the most recent news, Gliese 581 is suspected to contain up to 4 exoplanets (Vogt et al 2010). 

Now a new paper out by Steven S. Vogt, R. Paul Butler, and Nader Haghighipour re-examines the previous HARPS data for the Gliese 581 system. They found that previous attempts to examine the system (Forveille et al 2011) excluded outlying data points. Re-examination of the numbers by Vogt's team confirmed the same 4 planers previously known as well as some additional worlds, including confirmation of the now famous Gliese 581g:

"The periodogram of the residuals to a 4-planet all-circular-model reveals significant peaks that suggest one or more additional planets in this system. We conclude that the present 240-point HARPS data set, when analyzed in its entirety, and modeled with fully self-consistent stable orbits, by and of itself does offer significant support for a fifth signal in the data with a period near 32 days."

The Signatures of Intelligence

Blue Marble 2012 - Can you detect life in this picture? 

Looking for lifeforms out there in the Milky Way Galaxy is a very difficult task. Why so hard? You might say to yourself, "Well, I'll know a living thing when I see it." And generally, with the exception of a sea sponge or a slime mold, that is basically true. But, try recognizing something hundreds of millions of miles away, as is the case with Mars, or hundreds and hundreds of light years away, as is the case with most of the exoplanets we are discovering. In light of such a complication, the business of looking for life comes down to looking for signs of life. In order to do this, one must understand what kinds of life signatures can exist. A knowledge of all the different ways that lifeforms can alter their environment can give us an itemized list of what to look for on other worlds.

So, when scientists get a whiff of an alien atmosphere, as is the case sometimes when an exoplanet is detected by Astronomical Transit, they breakdown the light via spectroscopy and sift through the results looking for key atmospheric gases like oxygen or methane. These kinds of gases are signs of life, as far as LAWKI is concerned (Life As We Know It)...these gases in particular are waste products of the living metabolisms of millions upon millions of creatures. Another sign of life for LAWKI is water, and indeed water is being sought after like the holy grail as far as exoplanet discoverers and astrobiologists are concerned. Just recently, there has been chatter about how to discover exo-oceans - oceans on other worlds - by understanding how light from the parent star can reflect off of that ocean. It is crude to look for life in such a way, but at the moment our options are quite limited. What we need is to broaden our thinking on how particular biological patterns leave particular signatures in the environment they inhabit.

MSL Curiosity to Land in 20 Days

For those of you who might not have heard, the Mars Science Laboratory Curiosity - the most advanced human-made object ever sent to another world - will be landing on Mars Aug 6 2012 at approximately 1:31AM Eastern Daylight Time, or if you prefer, 10:31 pm Aug 5 2012 on the West Coast (or, more appropriately 5:30 am UTC).

While its true that we've been to Mars before, gigantic questions still linger unapologetically in our faces...Questions like, "Did Mars ever have life?" or "Was Mars truly ever a wet planet?" or "Can Mars support Human colonization?" or "What happened to Mars, to its magnetosphere, to turn a perfectly good world into a cold, barren platform for the political maneuvers of the Baron Vladimir Harkonnen?"

The fact is, we know very, very little still about our nearest planetary neighbor. What we can tease out of Mars over the next few years with Curiosity is going to add much to the Search for Life, to our understanding of what is required of a rocky planet to support the creation of life. Mars and Earth are so very similar in many ways, so much so that it appears now, in this pre-Curiosity period, that we are dealing with a kind of Tale of Two Planets. Earth and Mars both seemingly started in the same situation billions of years ago and took two different paths in their planetary lives - Earth headed for the whole teeming-with-life gig while Mars got the Tatooine treatment.

New King of the Galaxy Crowned

The Bad Astronomer (found at Google+, Twitter, Facebook and of course the Bad Astronomy Blog) leads on the story of the star HD 10180, which is a star you can't see with the naked eye, but is readily seen with a telescope. It is in the Hydrus constellation, if your are familiar with your constellations (Hydrus has four stars with planets!). According to a reassessment of the data concerning this star, it seems it possesses nine planets. If you are counting, that is one more planet than our own solar system (or Sol System, if you prefer) contains, if you accept Pluto's current status (RIP Pluto). So, the score so far on the solar system with the most planets is...

HD 10180         9 Planets          Status: King of the Galaxy
Solar System    8 Planets           Status: Runner-up
Kepler 11          6 Planets           Status: Never wins at anything

Horizontal Gene Transfer

Eastern Emerald Elysia - a sea slug. Photo by Patrick Krug of the
Encyclopedia or Life

Everyone knows the usual story of evolution. An organism wishes to pass on its genes to the next generation must do so by surviving and reproducing in a dynamic environment. It must evade predation, avoid the pitfalls associated with weather, find enough food to make it to the next day and convince a partner (if the organism reproduces sexually) to mate in order to pass on those genes. If the genes are well-suited to the context in which it evolved, then the next generation will be given the necessary tools to continue the same struggle. If the genes are not well-suited for some reason, or the environment or competition is too harsh, then the survival of the organism becomes questionable. This story works because of a mechanism we will call Vertical Gene Transfer (VGT). This is where genes are passed from parent to offspring through reproduction.

So, in light of this scientific truth, it may be surprising to know that VGT isn't the only game in town. There is a thing in the world called Horizontal Gene Transfer (HGT). Certain organisms are capable, it seems, of exchanging genes in ways that DO NOT involve the standard sexual or asexual reproduction model. There are several different ways in which HGT can happen:

Thoughts on Life’s Diaspora

Here is a continuation of the discussion regarding Panspermia, which is the idea that life can move from one planetary body to another, in effect seeding a lifeless world. It is a claim that is passed off as science fiction conjecture, in some circles; as perhaps a claim not entirely worthy of scientific investigation. Others, both scientists and laypeople, helpfully counter that the idea of panspermia, as it concerns the origins of life on Earth, is just passing the problem from one place to another without answering the fundamental question, which is "How did life first arise?"

I disagree with the first point, and largely agree with the second. The search for life outside of the Earth IS a goal worthy of scientific investigation. Due to the very reasons that the origins of life are, thus far, inexplicable, so should we regard with seriousness the search for extraterrestrial life as part of the effort to understand the mystery of life's origins. We have no clear answers as to why life arose here on Earth. Even if we do find that mysterious genesis and it sheds some light on the process, we will probably not have a clear understanding of the events that transpired in life's first steps. That will be the case until we have a clear, unambiguous example of non-Earth life with which to compare us to.

Optimism at SETICON 2 and Beyond

The SETICON 2 event happened this past weekend in Santa Clara, California. The SETICON is a "unique, entertaining and enlightening public event where science and imagination meet." Speakers such as SETI pioneer Frank Drake, astronauts Mae Jemison and Tom Jones, Star Trek veteran Robert Picardo, SETI director Jill Tarter, exoplanet explorer Geoff Marcy among many other notable people attended and mingled, marinating in the ideas and the presence of influential personalities.

It seems that everyone is excited. There is a palpable post-SETICON 2-buzz filling the internet this week as a result of all that scientific and creative merging. What is the general theme that the rest of us sense? Optimism. 

The reason is this: we can't possibly be living in more interesting times. The entire planet, in one way or another, is connected via planetary, near-instantaneous computer network that is having profound impacts across all aspects of life. The rate at which we solve problems is increasing exponentially, which seems to be leading to the abundant future recently described by Peter Diamandis. And most intriguingly, we've been discovering hundreds of planets outside of our solar system at an intense rate.

The Kepler Spacecraft

The fixed point of view for the Kepler Spacecraft

There are various ways in which humanity has begun detecting the presence of extrasolar planets, that is to say planets outside of our own solar system. Perhaps one of the most remarkable of these methods is that of the Kepler Observatory Spacecraft. It is a spacecraft like no other. It is a planet hunter. Its only job is to look out into the stars that surround us and detect candidate planets. It has been running for a little over three years now and it has turned up 2,321 candidate planets, 74 of which have been confirmed (as of this post). For most of us, this is difficult to imagine. Only 20 years ago or so, the only planets we knew about were the ones in our home solar system. Now, there are literally thousands of possibilities...planets upon planets out there in the galaxy around us. These happy discoveries still stun us, still excite our senses and the prospect of discovering even more planets in the future is very promising.

Observing these exoplanets is not an easy task. They are not immediately detectable, or even visible, from our star system. The Kepler Observatory uses the Astronomical Transit Method in order to infer an exoplanet's existence. This consists of observing a star's total amount of emitted light, measuring it and watching for changes in that amount of light. Noticeable and perhaps regular fluctuations can be an indication that a planet is passing in front of its star relative to our position in space. This could indicate an orbiting planet, which would block a detectable amount of light in regular intervals. The longer that Kepler observes a star, the greater the chance that a planet will show itself. Naturally, longer observations are better than short ones.

Arsenic-DNA Bacteria Disputed

In 2010, the journal Science published a paper by NASA Astrobiologist Felisa Wolfe-Simon and her team, which describes a rare extremophile found in Lake Mono, California. This bacteria, labeled GFAJ-1, appeared to be able to switch out the life essential element phosphorus for that of the chemically similar, but poisonous element arsenic. The implication was that if life on Earth could be persuaded to take in and use arsenic, which is very poisonous, then the possibilities for extraterrestrial life can be broadened to include arsenic-using organisms. it was a finding that immediately caused a stir in the scientific community. Now, two papers out in Science refute this arsenic-for-phosphorous claim.

Mono Lake is a promising place to look for extremophilic behavior. The waters there have high levels of arsenic and a productive ecosystem based on brine shrimp that thrives despite arsenic's poisonous nature. The temptation to see just how well-adjusted that ecosystem is to elemental arsenic is understandable. Felisa Wolfe-Simon led a research team to investigate this possibility and claimed to have found the bacteria GFAJ-1 substituting phosphorous for arsenic. The claim, more specifically, indicated that the bacteria was able to incorporate small amounts of arsenic in place of phosphorous in the bacteria's DNA and do so successfully, making it the first known lifeform on Earth to do this. The results were published in Science in December of 2010 and quickly caused consternation among some in the scientific community.

The Tardigrades: Earth's Toughest Lifeform?

Photo courtesy of http://www.sciencephoto.com

Hank Green gives us a quick introduction to the Tardigrades, a kind of extremophile. Tardigrades, sometimes known as "Water Bears" or "Moss Piglets" live in water, have eight legs, feed on moss, and are very small - microscopic, in fact. They live worldwide in many different altitudes and environments including various levels of the ocean. They are known as very tough organisms, despite being so tiny. NASA sent these guys into space just to see if their reputations for toughness bear out. It turns out that Tardigrades are, unusually, one of the toughest organisms on Earth.

They were sent into space and tested in two controlled sets of populations. The first water bear population set was exposed to both the vacuum of space and to the solar radiation emitted by the sun. The second population set was exposed to just the vacuum of space and NOT the harmful solar radiation. Many of the Tardigrades survived the exposure and the trip back to Earth, where some of them even reproduced after their experience.

One of the implications of this experiment informs us on the possibilities of Panspermia. Panspermia is the idea that life can be seeded onto a dead world, perhaps naturally...that life is tough enough to survive a journey from one planetary body to another in a solar system. The Tardigrades's experience in space certainly opens up the possibility of a Panspermiated Solar System. if they can survive this, then what else is possible? Check out Hank Green's video below. After the video, check out some gnarly Water Bear photography #WaterBearPorn

Isn't he cute? Photo courtesy of http://www.sciencephoto.com

What is Project 1640?

Detecting Extrasolar planets is tough work. Most of the detections gave been indirect (only 5% of exoplanets have been observed directly). Now, a new promising method of exoplanet detection is debuting and it is called Project 1640. However, before we describe what Project 1640 is all about, let's review all the current methods that we can use to detect an extrasolar planet outside of our Solar System:

1) Radial Velocity Method: AKA Doppler Spectroscopy. This method basically watches for a star to wobble. What does a star wobble mean? It means that the star is being gravitationally affected by its own orbiting planets. Both planet and star both tug on each other through gravity. Have you ever spun in a circle with a friend, hands locked together? Did you notice that you kind of have to lean back in order for both of you to spin smoothly. What this does is it creates a kind of "center" between the both of you. Suns and their planets do the same thing. As they spin together, the sun will oscillate back and forth - wobble in place - in accordance with the strength and speed of the planet that is orbiting. This method excels at detecting planets larger then Jupiter, generally. This is because larger planets cause their parent stars to wobble considerably more than smaller planets, thus making the star's wobble easier to detect. This wobble effect is detectable because of the Doppler Effect. The frequency of light waves change as the object emitting them is in motion. And this change in frequency is detectable.